Tires having decorative sidewalls have been well known and well received in the market. White or colored sidewall bands are commonplace, as are sidewalls having decorative lettering or any of various geometric designs thereon. Such decorative sidewalls have previously been constructed by use of a coextrusion process of black rubber along with colored or white rubber. Such a process is expensive, time consuming, and given to excessive waste. Further, decorative sidewalls are becoming an increasingly significant portion of the sidewall structure itself, but the coextrusions just mentioned are not ideal for structural integrity. Separate tire bodies are developed for black wall tires as distinguished from those tires which ultimately receive a decorative sidewall as by the application of a coextrudate of different rubber compounds. It has further been known that the generation of decorative sidewalls other than by the application of bands has been somewhat limited as to design and color, since variations in such decorations have previously required sophisticated and expensive dyes, molds, and the like.
Copending patent application Ser. No. 766,227, filed herewith, and assigned to the Firestone Tire & Rubber Company, the assignee of the instant application, sets forth a structure and technique which is a significant departure from the prior techniques discussed above. According to this copending application, a polymeric paint may be applied to a thermally stable substrate such as acetate, polyester, or treated paper, in a desired configuration such as a continuous band, selected lettering, or geometric designs. The substrate is placed into the tire curing mold with the polymeric paint in contacting engagement with a green tire. The tire is cured at an elevated temperature and pressure in standard fashion with the polymeric paint being transferred to the tire during the curing operation. The tire is removed from the mold with the substrate remaining on the decorative area, not to be removed until the tire is placed into use. In effect, the substrate serves as a protective coating for the decorative area of the sidewall, as well as a carrier for the applique when it is placed into the tire mold. The substrate is easily removed from the tire after curing because the adhering force of the polymeric paint to the tire due to the curing operation is significantly greater than the adhering force between the paint and the substrate.
While the substrate of the copending patent application serves well as a protective coating for the decorative applique during shipping, storage, and handling, the substrate is not sufficently firm to be easily handled and placed in the tire mold. Further, the substrate is not reuseable, but by its nature is disposable. Such a flexible substrate is difficult to register within the mold so as to guarantee that the substrate and applique is properly positioned with respect to the green tire. With a flexible substrate, the sidewall band deposited thereby may lose concentricity and integrity during mold closure. Finally, substrates of the type proposed in the copending application are not given to use in an automated process wherein a robotic arm may be required to place the decal-bearing substrate in the mold prior to curing and remove the substrate from the mold after curing.